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Biomedical subjects

T P Brown

Publications and source records attributed to T P Brown.

At least 19 recordsLinked to original sources
PubMed2006

Intervention development in occupational research: an example from the printing industry.

BACKGROUND: Intervention development research is an essential prerequisite of any study that attempts to determine whether specific interventions work to prevent work related injury and illness. METHODS: Focus groups (n = 5) and direct observational studies (n = 21) of printers were used to elicit key issues that would aid the development of subsequent interventions. Transcripts from these were analysed by standard qualitative methods to identify common and related themes. RESULTS: The views of managers differed significantly from those of print workers in a number of areas, and working practices did not always follow policy. The majority of printers did not perceive dermatitis to be a major problem, although many complained of dry hands. Other key results included: the lack of skin care policy in most companies; poor understanding of the nature, causes, and treatment of dermatitis; low priority of dermatitis within health and safety concerns; little or no provision of occupational health services, particularly skin checks; variability in provision of and access to appropriate skin protection; and lack of accessible washing facilities. CONCLUSIONS: As a result it was decided to evaluate the implementation of four INTERVENTIONS: provision of (1) skin checks and treatment advice; (2) gloves of the correct type and size, and use of an after-work cream; (3) information on dermatitis within the printing industry; and (4) development of best practice skin care policy.

Attitude to Health↗
PubMed2005

Mortality in the UK industrial silica sand industry: 1. Assessment of exposure to respirable crystalline silica.

AIMS: To develop a job-exposure matrix (JEM) from personal and static respirable crystalline silica (RCS) measurements in UK industrial silica sand workers. METHODS: A total of 2429 personal and 583 static RCS dust samples were collected using cyclone samplers at seven UK quarries between 1978 and 2000. These data were combined, and analysis of variance using general linear models was used to evaluate the effect of quarry, job, and year on RCS concentrations, and facilitate the creation of five quarry and three time categories with similar exposure levels by comparing the least-square GM RCS concentrations. RESULTS: The overall geometric mean (GM) RCS concentration was 0.09 mg/m3 (geometric standard deviation 3.9). Silica flour and dry job categories tended to have the highest RCS exposure and 13.3% of all samples exceeded the UK maximum exposure level of 0.3 mg/m3. RCS levels generally decreased over time. CONCLUSIONS: Data have been collected and used to develop a JEM for UK industrial silica sand workers between 1978 and 2000. Although there were some limitations in the data and certain assumptions were made, the use of available data to estimate exposure quantitatively is an improvement over the use of qualitative and surrogate measures of exposure. The continual collection of dust measurements in the industry is essential to facilitate the exploration of exposure-response relations that may exist between silica and silicosis, lung cancer, and other diseases.

Air Pollutants, Occupational↗
PubMed2005

Mortality in the UK industrial silica sand industry: 2. A retrospective cohort study.

AIMS: To evaluate the mortality experience of a cohort of employees in the UK silica sand industry exposed to respirable crystalline silica (RCS). METHODS: A retrospective cohort mortality study followed all workers to 2001 with at least one year's employment at one of seven UK silica sand producing quarries between 1950 and 1986. Each worker was assigned a job category and cumulative exposure to RCS was estimated using a job-exposure matrix. RESULTS: A total of 764 deaths were identified in 2703 cohort members. The overall mortality rate for the cohort was lower than would be expected in the general population. Mortality from circulatory and respiratory disease was also less than expected, but death due to pneumoconiosis was slightly raised (two deaths). Mortality from all cancers was slightly decreased. Mortality was not raised in any job category. Cancer mortality was raised at one quarry due to a significant increase in lung (standardised mortality rate (SMR) 162.0, 95% CI 113.5 to 224.3) and bladder (SMR 366.5, 95% CI 167.6 to 695.7) cancers. Mortality from lung cancer and other causes did not show a trend with cumulative exposure to RCS. CONCLUSIONS: This study did not show any consistent relation between RCS exposure (in the absence of other known carcinogens) and the development of lung cancer. This contrasts with a number of studies that have shown positive findings in similar and related industries.

Aged↗
PubMed2005

Reproduction of proventriculitis in commercial and specific-pathogen-free broiler chickens.

Proventriculitis was studied by experimentally reproducing the disease in broiler chickens. One-day-old infectious bursal disease virus (IBDV) and infectious bronchitis virus (IBV) antibody positive commercial broilers and 1-day-old antibody negative specific-pathogen-free (SPF) broilers were orally gavaged with proventricular homogenates produced from the proventriculi of broilers with proventriculitis. At 7 and 14 days, both commercial and SPF broilers had enlargement of the proventriculus with necrosis of the glandular epithelium and lymphocytic infiltrates in the proventricular glands. SPF broilers exposed to the proventricular homogenates developed infectious bursal disease, and IBDV was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). They also were positive by RT-PCR to IBV and developed nephritis. Commercial broilers developed mild nephritis but not bursal disease and were negative for IBDV and positive for IBV by RT-PCR. Both homogenate-inoculated commercial and SPF chickens were negative for reovirus and Newcastle disease virus by RT-PCR and variably positive for adenovirus by PCR. Bacteria were not identified in histologic sections, nor were they isolated from affected proventriculi. Indirect fluorescent antibody assay using convalescent sera detected intracytoplasmic staining in the proventricular glandular epithelial cells. Examination of thin sections of proventriculi using electron microscopy identified virus-like particles approximately 120 nm in diameter within the cytoplasm of these cells at 7 days after inoculation. Passage of proventricular homogenate filtrates in chicken embryos for virus isolation caused stunting, and allantoic fluid from these eggs was positive for IBV by RT-PCR.

Animals↗
PubMed2004

Proventriculitis in broiler chickens: immunohistochemical characterization of the lymphocytes infiltrating the proventricular glands.

Broiler chickens with transmissible proventriculitis have severe lymphocytic infiltration of the proventricular glands. The distribution of T cells and B cells in these infiltrates was studied histopathologically, and their identity was confirmed immunohistochemically (CD3, CD4, CD8, and B cells). To reproduce this disease, 1-day-old commercial boilers were orally gavaged with homogenized proventriculi from broilers with proventriculitis. Resulting lesions were examined at both acute (7 days postinoculation [i]) and chronic (14 and 21 dpi) time points. Lymphocytic infiltrates in the proventricular glands and the mucosal lamina propria were present at all time points and were most prominent and demarcated at 14 dpi. T and B lymphocytes were present during acute and chronic proventriculitis, but their distribution varied within the glands. Lymphocytic infiltrates in the proventricular glands and in the lamina propria were predominantly CD3+T cells, and most of these were also CD8+. B cells and CD4+ T cells formed aggregates in chronic proventriculitis. Thus, both cell-mediated and humoral immune responses are induced during transmissible proventriculitis, and the cell-mediated immune response is morphologically greater.

Animals↗
PubMed2002

Cardiomyopathy in broiler chickens congenitally infected with avian leukosis virus subgroup J.

Dilated cardiomyopathy and ascites in broiler chickens are frequently associated with rapid growth and pulmonary hypertension, but can be associated with some avian leukosis virus (ALV) infections. The novel subgroup J of ALV has a high cardiac tropism, but dilated cardiomyopathy has not been reported previously. We report a dilated cardiomyopathy incidence of 11.1% in broiler chickens congenitally infected with ALV subgroup J (ALV-J). Gross lesions included severe body weight suppression, cardiomegaly with biventricular dilation, right ventricular hypertrophy, visceral congestion, and ascites. Cardiac myocytes and Purkinje fibers contained 2- to 10-microm intracytoplasmic magenta inclusions that contained ALV-J-specific nucleic acid. Ultrastructurally, inclusions contained ribosomes and immature virions and were associated with myofibril disruption and disarray. Peracute centrilobular hepatic necrosis was present in most cases. ALV-J-associated cardiomyopathy may involve a direct viral effect on cardiac myocytes and Purkinje fibers.

Animals↗
PubMed2001

Passive antibody to Bartonella henselae protects against clinical disease following homologous challenge but does not prevent bacteremia in cats.

We challenged cats transfused with anti-Bartonella serum and kittens born to antibody-positive queens with Bartonella henselae to determine the contribution of antibodies to the control of B. henselae in cats. In both experiments, antibody-positive cats were protected from clinical disease but passive antibody to the homologous strain of B. henselae did not prevent bacteremia.

Animals↗
PubMed2001

The possible effects on health, comfort and safety of aircraft cabin environments.

A consultation was undertaken to investigate the views and concerns of stakeholders in the aircraft industry about the possible harmful effects on personal health, comfort and safety of aircraft cabin environments. Stakeholders were identified from a variety of sources including Government agencies, the Internet, House of Lords inquiry, and suggestions of interviewees. They represented: aircraft crews, aircraft constructors and engineers, government departments and authorities, holiday/flight companies, insurance companies, non-governmental organisations, occupational health physicians, passenger representatives, and independent researchers and consultants. Eighty-seven were contacted of which 57 were interviewed over the telephone using a semi-structured questionnaire. Their concerns were transcribed into a standard format and analysed qualitatively. Key stakeholders, along with Government officials, were invited to a workshop to discuss and prioritize the issues raised during the interviews. The main concerns expressed by the participants fell into five main areas: deep vein thrombosis, air quality, infection, cosmic radiation, and jet lag and work patterns. In addition, a number of safety concerns were raised as well as comments on the provision of appropriate advice to passengers. It was generally felt that further research was required on each of these subjects, as well as an improvement in the quality, quantity and availability of information provided for passengers prior to boarding a flight.

Air Pollution, Indoor↗
PubMed2001

Heterophil function and resistance to staphylococcal challenge in broiler chickens naturally infected with avian leukosis virus subgroup J.

Avian leukosis virus subgroup J has a high tropism for myeloid lineage cells and frequently induces neoplastic transformation of myelocytes. The impact of congenital avian leukosis virus subgroup J infection on the function of circulating heterophils and susceptibility to staphylococcal infection was investigated. Six-week-old broiler chickens negative for exogenous avian leukosis viruses or congenitally infected with avian leukosis virus subgroup J were inoculated intravenously with 10(6) colony-forming units of Staphylococcus aureus, and pre- and postinoculation heterophil function was assessed. All chickens developed a leukocytosis with heterophilia after inoculation, but total leukocyte and heterophil counts were significantly higher in leukosis-negative chickens than in virus-infected chickens. Tenosynovitis was more severe in leukosis-negative chickens, and 2/10 (20%) of the virus-infected chickens had no histologic evidence of tenosynovitis. Osteomyelitis in the tibiotarsus or tarsometatarsus developed in 5/10 (50%) of the chickens in each group. S. aureus was recovered from the hock joint of 6/10 (60%) of the chickens in each group. Heterophils from all chickens exhibited similar phagocytic ability pre- and postinoculation. Heterophils from virus-infected chickens exhibited less bactericidal ability preinoculation than did heterophils from leukosis-negative chickens. However, postinoculation bactericidal ability was similar in both groups. Avian leukosis virus subgroup J provirus was present in heterophils isolated from congenitally infected chickens. Heterophils isolated from broiler chickens congenitally infected with avian leukosis virus subgroup J exhibit no significant functional deficits, and infected and uninfected chickens exhibit similar susceptibility to staphylococcal infection.

Animals↗
PubMed2001

Localization of avian leukosis virus subgroup J in naturally infected chickens by RNA in situ hybridization.

The novel subgroup J of avian leukosis virus (ALV-J) has emerged as a significant cause of myeloid neoplasia and weight suppression in broiler chickens. We investigated viral tropism using RNA in situ hybridization (ISH) in naturally infected chickens. Formalin-fixed tissues were collected from 12-day-old embryos (seven infected, two control) and from 0-week-old (four infected, one control), 3-week-old (five infected, one control), 6-week-old (five infected, one control), and 9-week-old (10 infected, two control) chickens naturally infected with ALV-J in ovo. A 636-base antisense riboprobe complementary to the 3' and 5' ends of the pol and env viral genes, respectively, was constructed. Strong positive staining was present in cardiac myocytes, Purkinje fibers, vascular and pulmonary smooth muscle, renal glomeruli, distal tubules, and pituitary glands. Light staining was present in gastrointestinal smooth muscle, thyroid and adrenal glands, and follicular medullae in the cloacal bursa. Staining was not present in any hematopoietic precursors. Tissues from newly hatched chicks exhibited the strongest and most consistent staining, whereas staining in embryos was minimal. RNA ISH confirmed the presence of ALV-J-specific nucleic acid within cytoplasmic inclusions in cardiac myocytes, Purkinje fibers, pituitary glands, and renal glomeruli. Viral tropism for cardiac myocytes and Purkinje fibers may relate pathogenetically to the cardiomyopathy and congestive heart failure described in index chicken flocks infected with ALV-J. Viral tropism for endocrine organs may relate pathogenetically to the weight suppression associated with infection.

Animals↗
PubMed2000

Peptic ulcer bleeding: accessory risk factors and interactions with non-steroidal anti-inflammatory drugs.

AIMS: To determine risk factors for peptic ulcer bleeding other than non-steroidal anti-inflammatory drugs (NSAIDs). Methods-Data on possible antecedent risk factors obtained in a large case control study of 1121 patients admitted to hospitals in Glasgow, Newcastle, Nottingham, Oxford, and Portsmouth with bleeding peptic ulcers were compared with the same information obtained in 989 population controls. Data were analysed by logistic regression with the calculation of odds ratios (OR) and 95% confidence intervals (CI). RESULTS: From a logistic regression model, oral anticoagulants (OR 7. 8; 95% CI 2.8-21.5), previous peptic ulcer (3.8; 2.6-4.9), treatment for heart failure (5.9; 2.3-13.1), oral corticosteroid use (2.7; 1. 3-4.5), treatment for diabetes (3.1; 1.2-4.3), and current smoking (1.6; 1.2-2.0) were all independent risk factors. No association was found with use of calcium channel antagonists. Odds ratios for concomitant NSAID usage were multiplicative with the exception of current smoking. CONCLUSIONS: Some 45% of admissions for peptic ulcer bleeding in England and Wales in those aged 60 or more are calculated to be attributable to, or associated with, these accessory risk factors, which, together with those associated with aspirin or other NSAID use will account for over 80% of predisposing factors to ulcer bleeding.

Aged↗
PubMed1999

A method of assessing female breast morphometry and its clinical application.

A series of reproducible measurements have been developed with reference to a single midline datum that describe the position of key landmarks on the female breast. Measurements were made on a 'normal' population of 60 subjects content with their breast shape in order to (1) produce 'normal' reference data for breast shape in a population of varying weight and height; and (2) to evaluate factors which may influence the measurements. The findings show that the vertical positions of the measurements migrate inferiorly with increasing age. With increasing weight, the landmarks (except the medial end of the inframammary crease) migrate inferolaterally. Areolar diameter decreases with increasing age and increases with increasing weight. Only one of the 12 bilateral breast measurement parameters shows a significant mean difference between the right and left breast. However, in a proportion of subjects, individual measurements show fluctuating asymmetry. Subsequently, measurements were made of the breasts of women attending with requests for either reduction (n = 25) or augmentation (n = 6) mammaplasty. Compared with the 'normal' population, the group requesting reduction mammaplasty differed significantly in the majority of measurements. The group of patients requesting breast augmentation showed fewer differences compared with the 'normal' population. The average BMI of women requesting augmentation mammaplasty was significantly less and that of women requesting reduction mammaplasty significantly greater than the normal population. In conclusion, a simple and reproducible method of morphometric measurement of the female breast is described. Application of this method suggests that patients requesting reduction or augmentation mammaplasty on the NHS represent a significant deviation from 'normal' morphometry and do not simply have a subjective distortion of their own body image.

Adolescent↗
PubMed1998

Methicillin-resistant Staphylococcus aureus in burns patients--why all the fuss?

Procedures designed to limit spread of methicillin-resistant Staphylococcus aureus (MRSA) in burns units demand time and resources. To assess the significance of MRSA in burns patients we performed a retrospective review of MRSA colonization in in-patients over a 41-month period at the North Trent Sub-regional Burns Unit. Patients were compared with MRSA free controls, matched for age and percentage body surface area (BSA) burn and admitted during the same time period. Length of stay, number of operations and deaths were outcome indicators. All patients managed non-operatively were excluded, leaving 40 MRSA patients and 46 controls. There was no statistical difference between the two groups with regard to number of operations (p= 0.07), duration of admission (p = 0.12) or mortality (p = 0.09). Of the control group, 83% had wound swabs positive for methicillin-sensitive Staphylococcus aureus (MSSA). there was no statistical difference in any outcome variables between this sub-group of controls and MRSA patients. Colonization with S. aureus (both MRSA and MSSA) was associated with larger burns (p<0.05), twice as many operative procedures (p<0.05) and prolonged admissions (p<0.01). Mortality was unaltered by staphylococcal colonization (p = 0.8). Although our study lacks power, we would suggest that methicillin resistance per se is not associated with increased morbidity or mortality in burns patients.

Adult↗
PubMed1996

Mortality pattern among biological research laboratory workers.

A cohort study was conducted to investigate the mortality of individuals employed by biological research institutes in the UK. The inclusion criteria were met by 12,703 individuals, of whom 95% were traced (11,502 alive, 395 deaths, 246 embarkations). All-cause mortality was significantly reduced in men (standardised) mortality ratio (SMR) 55 and women (SMR 52). Mortality was also significantly reduced for circulatory and respiratory diseases, and overall there was low mortality from malignant neoplasms. SMRs exceeded 100, but were not statistically significant, for infective and parasitic diseases. There were no statistically significant raised SMRs for any cancer site. Workers were categorised as ever worked in a laboratory (laboratory workers) and never worked in a laboratory (non-laboratory workers). The all-cause SMR was significantly reduced in both groups, as was mortality from circulatory and respiratory diseases. The SMR for malignant neoplams was also significantly reduced in laboratory workers. On the basis of follow-up to 31 December 1994, there is no evidence of any overall increased risk of mortality in biological research laboratory workers. However, the power of the analysis is limited by the young age of many cohort members and short duration of follow-up. Follow-up is continuing and the data will be reanalysed once more deaths have accumulated.

Agriculture↗
PubMed1994

Middle ear symptoms while flying. Ways to prevent a severe outcome.

In an era when air travel is commonplace, middle ear block is not unusual. Educating patients about the simple techniques they can perform at the first signs of a problem may save a business trip or vacation from becoming a trip to the emergency department and a train ride home. The most important preventive measure is to avoid flying when symptoms of upper respiratory tract infection are present. When this is not possible, passengers should yawn, swallow, or chew to relieve pressure in the middle ear. Use of the Valsalva maneuver and decongestants or antihistamines may be helpful. Serve or unremitting ear block may require the use of the Politzer bag or a myringotomy.

Aerospace Medicine↗
PubMed1993

Fumonisin toxicity in turkey poults.

The effects of dietary fumonisin B1 were evaluated in young turkey poults. The experimental design consisted of 3 treatments, with 24 female turkey poults allotted randomly per treatment. Day-old poults were fed diets containing 0 mg (feed control), 100 mg, and 200 mg fumonisin B1/kg feed for 21 days. Body weight gains and efficiency of feed conversion decreased linearly with increasing dietary fumonisin. Liver, kidney, and pancreas weights increased linearly with increasing dietary fumonisin, and spleen and heart weights decreased. Serum aspartate aminotransferase levels increased with increasing dietary fumonisin, and serum cholesterol; alkaline phosphatase, mean cell volume, and mean cell hemoglobin all decreased. Biliary hyperplasia, hypertrophy of Kupffer's cells, thymic cortical atrophy, and moderate widening of the proliferating and degenerating hypertrophied zones of tibial physes were present in poults fed diets containing fumonisin B1. Results indicate that fumonisin B1, from Fusarium moniliforme culture material, is toxic in young poults, and the poult appears to be more sensitive to fumonisin than the broiler chick.

Alkaline Phosphatase↗